Process for weeding



June 2, 1925. 1,540,427

A; SCHEUCHZER moczzss FOR WEEDI'NG Filed May' 5, 1924 Jam Patented June 2, 1925.

UNITED STATES PATENT OFFICE.

AUGUSTE SCHEUCHZER. OF RENENS, NEAR LAUSANNE, SWITZERLAND, ASSIGNOR TO FERRODESHERBEUSE SGl-IEUCHZEB SOGIETE ANONYME, OF RENENS, SWITZER- LAND.

Application filed May 5,

T 0 all whom it may concern:

Be it known that I, AUcUs'rr. SOHEUGH- znn, citizen of Switzerland, residing at Renens, near Lausanne, Switzerland, have invented certain new and useful Improvements in a Process for Veeding, of which the following is a specification.

The present invention relates to improvements in a process for weeding railroad tracks by mechanical means and especially to improvements for limiting the stroke of the knives employed.

There are already such machines having knives driven into the ballast so as to unroot the weeds between the rails and the sleepers. This process is performed by means of a servo-motor and generally by a steam-cylinder. The piston stroke is limited in one sense by the ballast itself, in the other sense however not always at one and the same distance. That is to say, that, when the cylinder operates the retreating movement of the knives, it becomes necessary to interrupt the stroke, partly in order to save time in the cycle of the operations partly in order to enable the knives to pass over the casual obstacles of the track as for instance at the level crossings.

Heretofore it was usual to employ a stepped check-plate and the different height of the steps of this plate were intercalated into the path of members integral with the piston rod of said servo-motor.

But in spite of springs which had been provided-for, there occurred much breaking of springs and even of the check-plate owing to the heavy and repeated kicks at each sleeper. Moreover it was of course impossible to provide steps enough on said plate to answer all the cases presented and there was also a limit given for regulating the re speetive stroke by the constructive dimensions of the member.

The present invention is intended to remedy this state of things by limiting the stroke by improved means. Thus a pneu niatic cushion or dash-pot has been provided on one side of an auxiliary piston which is connected by means of links and levers to 1924, Serial No. 711,301.

the weeding knife, the initial pressure of the cushion determining the length of stroke.

The single figure of the annexed drawing represents as an example a device for executing the process according to this invention.

The knives a are secured to the ends of bold ers a which are held slidably within brackets b pivoted at b on an eccentric 79 The oscillating movement of the knives is obtained by the reciprocating movement of a piston within a cylinder 0 and the steam admission, on either side of the piston is caused by a roller (Z dragged along through the ballast. The reciprocating movement of the piston is transmitted by a connecting rod to a bell-crank lever 7 which is pivotally mounted on the framing of the machine and kept in working connection with the holder a. of the knife by a link 9. The bell-crank lever f is likewise put into working connection with the piston 72, of an auxiliary cylinder i on the left hand side of which there is provided a compressed-air cushion fed from a reservoir arranged on the machine.

The moving piston of cylinder 0 will lift the knife, the said cushion will be compressed and when the pressure within cylinder i will become equal to the steam pressure within cylinder 0 equilibriumrwill exist and piston 0 will not move any farther. By the way of a simple two-way cook 70 it is then possible either to put the working side of cylinder h under pressure or to cause the exhaust of cylinder 2'. In the first case the stroke of the driving piston c is determined through the initial pressure of the cushion and in the second case the working conditions will be such that the piston 0 can execute its maximum stroke.

The exhaust ports of cylinder i are arranged at such a distance from the cylinder head that they are covered by the piston h before the piston of this cylinder is at the end of its stroke. Which fact is to the effeet that a constant aircush-ion is established which prevents an untimely collision between the piston and the cylinder head. On the free side of this piston which side will always be exhausted when the knives sink into the ballast the same precautionary measures are provided for. 7

Having now fully described the nature of my invention and the manner in which the same has to be perforn'ied, what I claim as new and wish to secure by Letters Patent is:

1. In railroad track weeding machines having knives which as may be required are introduced into and withdrawn from the ballast and worked by a servo-motor a process consisting in coupling the piston of a compressed air cylinder arranged coaxially With and facing the cylinder of the servomotor to the piston of this latter and to the operating member of the knife and in introducing air into the compressed air cylinder onthe piston side. facing the servo motor so as to counteract the movement 01 the piston of the servomotor and to have the length of stroke ofthe knives. determined by the initial pressure of the air cushion all as de scribed.

2. In railroad track weeding machines having knives which as may be required are introduced into and withdrawn from the ballast and worked by a servo motor and in combination a device for adjusting the up stroke of said knives and comprising a compressed air cylinder coaxially arranged with regard to the cylinder of the servo-motor, an angular lever pivoted on the framing links connecting the knives to the one arm of said lever and links connecting the pistons oith'e servo motor and of the compressed air cylinder to the other arm of said lever and means, like a two-way cock, adapted to form and to regulate an air-cushion on the pistonside facing the servo-motor substantially as shown and described. 7

In testimony whereof I affix my signature.

AUGUSTE SGHEUCHZER. 

